Pulmonary Physiology Review Flashcards

1
Q

What is the Conducting Zone of Ventilation

A

Trachea, Primary bronchus, bronchus, bronchi, bronchioles

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2
Q

What is the Transitional & Respiratory Zone

A

Respiratory bronchioles, alveolar ducts, alveolar sac

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3
Q

What is the purpose of multiple zones of ventilation?

A

greater surface area for gas exchange to occur on

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4
Q

Fick’s Law of Diffusion

A

Gas diffusions across a fluid membrane: inversely proportional to tissue thickness & directly proportional to tissue area, diffusion constant, pressure differential of the gas on each side of membrane

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5
Q

What happens when the pressure differential of a membrane is greater?

A

Greater gas exchange because greater spread of differential

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6
Q

Minute Ventilation (VE)

A

volume of air breathed each minute ( VE = breathing rate x tidal volume)

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7
Q

Alveolar ventilation

A

the process of inspired air reaching alveoli & participating in gas exchange (about 350ml/500ml of inspired tidal volume)

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8
Q

Purpose of alveolar ventilation

A

it determines gaseous concentrations at alveolar-capillary membrane

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9
Q

Anatomic Dead Space

A

the air that doesn’t enter alveoli and participate in gaseous exchange with blood (~150-200ml)

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10
Q

What are typical values for pulmonary ventilation during: rest, mod exercise, intense exercise

A

(Breath/min = 12, 30, 50); (TV= 0.5, 2.5, 3.0); (Pulmonary ventilation: 6, 75, 150)

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11
Q

Ventilation-Perfusion (V-P)

A

average ratio = 0.84 (0.85 L of alveolar ventilation for each L of blood flow)

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12
Q

Partial Pressure of gasses in ambient air

A

760mmHg (sea level)

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13
Q

What is the concentration of gases in ambient air?

A

~79% N2, 21%, 0.03% CO2

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14
Q

What is significant about tracheal air?

A

PO2 in tracheal air decreases by 10mmHg from ambient pressure, due to humidification (PCO2 effects are negligible)

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15
Q

What is significant about alveolar air?

A

Different bc CO2 continually enters alveoli from blood, and O2 continually enters blood from alveoli

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16
Q

How different is PO2 & PCO2 in ambient air, tracheal air, and alveolar air? mmHg

A

Ambient: PO2 = 159, PCO2 = 0.2
Tracheal: PO2 = 149, PCO2 = 0.2
Alveolar: PO2 = 103, PCO2 = 39

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17
Q

Henry’s Law

A

amount of gas dissolved in a fluid is proportional to partial pressure of the gas aver the liquid (when temp is constant)
(when equilibrium gets established between liquid & gas above it)

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18
Q

What factors determine the rate of gas diffusion into a fluid?

A
  • Pressure differential b/w gas above fluid & gas dissolved in fluid
  • Solubility of gas in fluid
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19
Q

What is significant about the solubility of oxygen?

A

its low solubility makes it easier to combine to Hb so it can dissolve into a fluid (pressure will increase to help..?)

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20
Q

What is significant about the solubility of CO2?

A

its high solubility means it doesn’t need any help dissolving into a fluid

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21
Q

How does CO2 travel from the blood into alveoli?

A

the pressure of CO2 in blood is greater than alveoli. Diffuses via pressure gradient

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22
Q

How does O2 travel from alveoli into the blood?

A

the pressure of O2 in the alveoli is greater than in the blood

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23
Q

what happens to N2 during gas exchange?

A

nothing, stays the same

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24
Q

How fast does alveolar gas-blood equilibrium occur?

25
Describe the pressure changes to O2 & CO2 as you inhale then exhale
Inspired are is PO2 =159mmHg, due to humidification PO2 becomes 149mmHg. Due to continuous gas exchange, PO2 =100mmHg & PCO2 = 40mmHg on average. Gases travel in the arterial blood until they get to the capillaries. Depending on the muscles metabolic demands, O2 will diffuse into the muscle & CO2 will diffuse out. Now, at rest PCO2 = 46mmHg & PO2 = 40mmHg & travels with the venous blood to the heart & back to lungs
26
What is unique about alveolar gas concentration?
it will stay stable even during strenuous activity that increases VO2 & VCO2 output 25 times resting values
27
What is the PO2 & PCO2 in muscles cells at rest & during excerice?
rest: PO2=40mmHg, PCO2=46mmHg Vigorous exercise: PO2=0mmHg, PCO2=90mmHg
28
How does blood transport O2?
1. loose combination with Hb (iron-protein molecule in RBC) 2. physical solution dissolved in fluid portion of blood
29
What is the function of O2 when transported in physical solution?
1. establishes PO2 of plasma & tissue fluids 2. helps regulate breathing, particularly at altitude 3. Determines O2 loading of hemoglobin in lungs & release in tissues
30
Facts about Hemoglobin
- 20mL of O2 is transported in each dL of blood - can carry 65-70x more O2 than dissolved in plasma - each Hb can carry 4 O2 molecules - PO2 dissolved ini physical solution determines if O2 binds to Hb
31
what is the oxygen-carrying capacity of Hb for men vs women?
men=15g Hb/dL blood; women=14g Hb/dL blood (1g of Hb combines with 1.34mL of O2)
32
How does an increase of temperature affect the oxyhemoglobin dissociation curve?
more off loading of O2 from the blood into the muscles (curve shifts down & right) - reason why you warm up muscles before competition - greater PO2 pressure means faster movement of O2 from blood to tissues bc following pressure gradient
33
How does a decrease of temperature affect the oxyhemoglobin dissociation curve?
O2 will bind to O2 for a longer time (curve shifts up & left) - less O2 available for tissues - lower PO2 means slower movement of O2 from blood to tissue bc pressure gradient
34
Which way does the oxyhemoglobin dissociation curve shift to an increase of acidity?
down & right - related to increase of H+ ions - Bohr affect
35
Which way does the oxyhemoglobin dissociation curve shift to a decrease of acidity?
up & left - related to decrease of H+ ions
36
What is P50?
when Hb is 50% saturated with O2 , PO2 = ~25mmHg
37
Explain the oxygen transport cascade (from the atmosphere to the mitochondria)
PO2: ambient air =159, tracheal air = 149, alveolar air = 103, arterial = 98, mean capillary = 40, myoglobin = 2-3
38
Explain the Bohr Effect
occurs when the oxyHb curve shifts down & right due to temp increases or plasma acidity. - O2 binding affinity is decreased bc H+ & CO2 alter Hb structure
39
What is the average PO2 in tissues and why is it significant?
40mmHg in cell fluids. This makes diffusion from plasma into the capillary membranes then tissues possible. the reduced PO2 in plasma lowers O2 saturation of Hb in RBC
40
Arteriovenous Oxygen Difference (a-vO2)
the difference of O2 in arterial blood & mixed-venous blood. average = 4-5mL O2/dL blood at rest
41
What happens to a-vO2 during exercise?
a-vO2 difference is greater. O2 release is increased 3x = ~15mL O2/dL blood O2 supply limits aerobic exercise capacity
42
Explain why RBCs cannot get saturated 100%
it produced a compound 2,3-DPG due to no mitochondria, and gets energy from anaerobic glycolysis
43
What impact does 2,3-DPG in the RBC have on O2?
O2 affinity is reduced due to the binding of 2,3-DPG with Hb Result: greater O2 release to tissues for a decrease in PO2 During strenuous exercise: 2,3-DPG aids O2 transfer to active muscles
44
How does the blood carry CO2 to the lung?
1. Physical solution in plasma (10%) 2. Combined with Hb within RBC (20%) 3. Plasma bicarbonate (60-80%) - transports via RBC
45
How does CO2 become bicarbonate?
in RBC of tissue, CO2 + H2O --> H2CO3 (w/ carbonic anhydrase) -then, H2CO3 --> H + HCO3 in lungs, H + HCO2 --> H2CO3 --> w/ carbonic anhydrase CO2 + H2O
46
What is the Haldane effect?
ability of deoxygenated Hb to carry more CO2 than in oxygenated state (from tissue to blood to lungs)
47
How does the Haldane effect help CO2 exit through the lungs?
CO2 moves into solution & then alveoli due to plasma PCO2 decrease in lungs (due to the reverse of carbamino formation)
48
Describe O2 & CO2 dissociation curves
PO2 a-vO2 difference = big - large pressure difference bw a-v for a low amount of O2 concentration - ex. v: O2 ~18 at PO2 of 40, a: O2 ~20 at PO2 of 100 result: greater pressure difference bw arterial & venous blood PCO2 a-vCO2 difference = small - small pressure difference bw a-v for a greater level of concentration of CO2
49
What are the partial pressure differenced for CO2 in the arterial and venous blood?
Arterial = greater PO2 & lower PCO2 Venous = greater PCO2 & lower PO2
50
What is a buffer?
mechanisms to minimize changed in H+ concentration (maintain homeostasis)
51
Define Alkalosis
decrease in H+ concentration (more basic)
52
Define Acidosis
increase in H+ concentration (more acidic)
53
What are chemical buffers?
bicarbonate, phosphate, protein buffers
54
How does sodium bicarbonate impact exercise performance? (buffer)
during exercise H+ content increases. sodium bicarbonate binds with H+ to reduce acidity result: prolonging energy metabolism to sustain power output during exercise
55
How is pulmonary ventilation regulated?
1. bloods chemical state (greatest control) ex. PO2, PCO@, pH, temperature activate neural units in medulla/arterial system to make adjustments 2. intricate neural circuits (i.e. sensors) ex. peripheral chemoreceptors receptors in the lung proprioceptors in joints & muscles core temperature chemical state of blood in medulla
56
What stimulates ventilation during exercise?
peripheral chemoreceptors - in response to increases in temperature, acidity, CO2, & potassium concentrations
57
Role of the carotid bodies
monitors state of arterial blood before it gets to brain tissue (if PO2 is low, it'll stimulate to increase ventilation)
58
Importance of Peripheral chemoreceptors
1. defend against arterial hypoxia for: - pulmonary disease - ascent to higher altitudes 2. help regulate exercise hyperpnea